In the manufacturing process of semiconductor components and electronic components such as a semiconductor wafer, a display glass substrate and a hard disc substrate, a polishing step is included for flattening and mirror finishing of the surfaces. The polishing step includes, in general, holding a member to be polished (hereinafter may be referred to as “work”) to the polishing head of a polishing device, fixing a polishing pad to a surface plate, and relatively sliding the member to be polished and the polishing pad in a pressurized state while supplying a polishing slurry.
In the polishing step, the most general means for holding and fixing the work to the polishing head is a fixing method using a holding pad. The holding pad is a sheet which has, on a joint surface to the work, a holding layer that is composed of a soft material having micropores in the surface of a polyurethane foam or the like. A method of using the holding pad includes having water enter between the holding pad and the work during a polishing operation, and having water enter the micropores in the surface of the holding layer to adsorb and fix the work with its surface tension.
Incidentally, at the time of the polishing operation using the holding pad, the operation is often performed while a form material for preventing lateral displacement of the work is joined and fixed to the holding pad. This form material, although some form materials having names such as a template and a retainer ring are known, includes a plate material having a hole similar to the shape of the work (hereinafter, for convenience, in the present invention, this form material is referred to as a template). Insertion of the work into the frame of the template constrains the work in a lateral direction, and thus prevents displacement of the work during the polishing operation.
Since as described above, the template is fixed to the holding pad in order to constrain the work in the lateral direction, if the template is easily separated, it does not work properly. Hence, in the manufacturing of the holding pad with the template, various improvements have been made, and for example, as in PTL 1, a primary layer is interposed between the template and an adhesive for bonding it, and thus the joint strength of the template is acquired.